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Mailsort Online - a bureau processing service

About Mailsort

Mailsort, Presstream and Walksort are special services offered by the Royal Mail, designed to save you money when sending bulk mail by post.

The basic idea is simple: The Royal Mail need to sort all letters by regional sorting office and put them in postbags marked with the code for the appropriate sorting office. This process is partly done by machine and partly by hand making it quite labour intensive, as each letter undergoes several of these sorting processes until it is finally delivered.

If however, you let a computer do the sorting work before the letters are even produced, the Royal Mail save a lot of work. In return they give you substantial discounts on the postage (see below for a few examples of the sort of money you can save).

What Mailsort Online does is exactly that. It can sort your mailing list in accordance with the strict guidelines set by the Royal Mail, and enable you to take advantage of these savings.

After you have selected the mailsort service you require and pointed to your mailing list, our system processes the file and informs you of the sorting result. This includes details on much money you can save as well as other statistical information about your mailing list. The process is very straight forward and only takes a few minutes from start to finish.

Our processors for Mailsort 1400, Mailsort 120, Presstream, Mixed Weights, Walksort and International Mailsort have all been accredited by the Royal Mail and comply fully with their sorting recommendations. The files and documents provided by our system are all you need to produce the labels of letters and use mailsort.




Entry requirements:

There are a few restrictions to be met before your list is eligible for Mailsort. Here are the most important of them:

  1. For Mailsort 1400, you will need to send a minimum of 4,000 Letter-sized items, or 1,000 Large Letters, A3 Packets or Packets in any single mailing.
  2. Postcode level must be at least 90%
  3. You must pack the postbags in accordance with the lists generated by this site
Click here to read more from the Royal Mail website.

Click here to run a free test against your mailing list to see if it qualifies. You also get a breakdown of your potential savings.


The discounts you can obtain depend heavily on the quality of the data and which service you choose. Read more on this below.

You can also find more comprehensive information in the Mailsort User Guides provided by the Royal Mail. Click here to open these guides from the Mailsort Technical Website.

Please note that in order to submit a mailsorted mailing to the Royal Mail you must first arrange a mailsort account with a Royal Mail Account Manager. Please contact the Royal Mail Sales Centre on 08457 950 950 to find out who your nearest Account Manager is. You can also click here to access the Royal Mail's own mailsort pages for more information.

When you have your Mailsort account, instead of purchasing or developing your own software, just return to this website to sort your mailing list in the required format. Click here to add Mailsort Online to your list of favourites




What do I need to do?

  1. Run a free test mailsort using this site to see if your mailing list complies with the entry requirements above.
  2. Get a Mailsort Contract from your nearest Royal Mail Account Manager (see the note above).
  3. Run the mailsort again using this site.
  4. Accept our processing fee in order to receive the mailsorted files and reports.
  5. Produce mailing and bag labels using the data files returned.
  6. Pack the letters into mail bags in accordance with the line-listing report provided.
  7. Deliver the mail bags to the post office (or arrange a pick-up by the Royal Mail)




Which Service should I use?

Mailsort Online currently support the following services:

  1. Mailsort 1400 and Presstream are the simplest services to use as there are fewer entry requirements to be met in order to get started. So for the majority of companies, and especially those new to Mailsort, these services are the best choice. Presstream for publications and Mailsort 1400 for ordinary letters or packets.

    You should select service 1, 2 or 3 based on how fast you need your items delivered versus how much you wish to save. Mailsort service 3 has the longest delivery time, but also the biggest discounts.

  2. Mixed Weight mailings are for Mailsort/Presstream 1400 where the letters are not all of the same weight. In order to run this the mailing list must contain the weight for each individual item, or a weight band code which is translated into an item weight as part of the process.

  3. Walksort is for mailings where the recipients are located within a relatively small geographical area. The letters are sorted to the individual postman walk, and in return you get a much bigger discount.

  4. International Mailsort is for mailings the same as Mailsort 1400 and Presstream, but where a number of recipients are located abroad. The international letters are bagged together in accordance with the service chosen and directed to the international sorting office at Heathrow.

    Please note that dockets must be submitted via the E*Pro online docketing service. Click here for further details. The import file for this purpose is included in the sorted data.

  5. Mailsort 120 uses "final bag labeling" and is only available to those whose entire mailing operations have been approved by the Royal Mail.




How much money can I save by running Mailsort, Presstream or Walksort?

Unfortunately there is no direct answer to this. It depends largely on the following factors:

  1. Which service you choose
  2. The geographical spread of your addresses
  3. The number of addresses in the mailing list
  4. The quality of your postcoding
  5. Your chosen minimum selection (higher savings with a small number)
  6. The weight of each letter.
The only real way to find out is to try sorting your mailing list and the e-mail we send you back will tell you how much based on the chosen service and minimum selection. Please note that the amounts and prices calculated by the system are only for guidance. The Royal Mail reserves the right to work out the exact amounts themselves when they receive the mailing.

Here are some examples using the same data file:

Example 1. Mailsort 1400 - 3, 20,000 items weighing 110g each (19,965 eligible items)
Total cost without Mailsort: £9,383.55 47 pence per item second class postal rate.
Total cost with Mailsort: £5,457.34 37.1 pence per item less discounts.
Mailsort Online processing fee: £15.00 minimum fee
Total saving: £3,911.21  


Example 2. Presstream 1400 - 2, 20,000 items weighing 110g each (19,965 eligible items)
Total cost without Presstream: £9,383.55 47 pence per item second class postal rate.
Total cost with Mailsort: £4,574.08 27.1 pence per item less discounts.
Mailsort Online processing fee: £15.00 minimum fee
Total saving: £4,794.47  


Example 3. Walksort 2, 20,000 items weighing 110g each (19,566 eligible items)
Total cost without Walksort: £9,196.02 47 pence per item second class postal rate.
Total cost with Mailsort: £4,275.55 37.1 pence per item less discounts.
Mailsort Online processing fee: £20.00 minimum fee
Total saving: £4,900.47  

(The prices used in the examples are correct as at 1 April 2005)




Data Quality

It is essential that the data quality requirements are met in order to qualify for a Mailsort Contract.

Firstly you must have a 90% Postcoding Level. This means that at least 90% of all the addresses have a correct postcode. For the remaining 10% we will try and match the town and county in order to get discounts on those as well. When this is done the ones that couldn’t be matched will be set aside to be posted normally.

If you have purchased address lists from third parties you will probably find a large amount of duplicates. There is therefore a potential saving in de-duping the list before you run Mailsort as you would otherwise send two or more letters to the same person. Please click here if you would like us to help with de-duping your mailing list.

Secondly the geographical spread of your mailing list will affect the discounts. Generally they are highest where there are lots of letters going through the same local sorting office. This is where the direct discounts apply, as opposed to residue discounts that apply where only a few letters go through a local sorting office and therefore revert to the regional sorting office.